1. Field of the Invention
The present invention relates to a vehicle occupant restraint system and a vehicle occupant restraint method for protecting a vehicle occupant by using an air bag in the case of a frontal collision of a vehicle.
2. Description of the Related Art
There exists a conventional vehicle occupant restraint system in which an air bag is equipped inside of a shoulder belt of a seat belt restraint device for restraining the shoulder and chest of a vehicle occupant, and the air bag is inflated and extended in the case of a collision of a vehicle, thereby protecting the vehicle occupant (refer to Japanese Patent Application No. 2004-232428).
Among vehicle occupant restraint systems in which the air bag is inflated and extended from the seat belt, as shown in FIG. 10, there exists a vehicle occupant restraint system in which two air bags, an upper air bag 3 and a lower air bag 4, are provided in a three-point seat belt restraint device 1 provided on a seat 2. The upper air bag 3 is supported by a shoulder belt 1a through an upper support point 5, and the lower air bag 4 is supported by a lap belt 1b through a lower support point 6. With such a construction, the upper air bag 3 with which the head of a vehicle occupant C interferes can be supported by the thighs of the vehicle occupant C through the lower air bag 4.